# TiKV Config

## Learn the TiKV configuration file

The TiKV configuration file supports more options than command-line parameters. You can find the default configuration file in etc/config-template.toml and rename it to config.toml.

This document only describes the parameters that are not included in command-line parameters. For more details, see command-line parameter.

## server

Configuration parameters related to the server.

### status-thread-pool-size

• The number of worker threads for the HTTP API service
• Default value: 1
• Minimum value: 1

### grpc-compression-type

• The compression algorithm for gRPC messages
• Optional values: "none", "deflate", "gzip"
• Default value: "none"

### grpc-concurrency

• The number of gRPC worker threads
• Default value: 5
• Minimum value: 1

### grpc-concurrent-stream

• The maximum number of concurrent requests allowed in a gRPC stream
• Default value: 1024
• Minimum value: 1

### grpc-memory-pool-quota

• Limit the memory size that can be used by gRPC
• Default: No limit
• Limit the memory in case OOM is observed. Note that limit the usage can lead to potential stall

### grpc-raft-conn-num

• The maximum number of links among TiKV nodes for Raft communication
• Default: 1
• Minimum value: 1

### grpc-stream-initial-window-size

• The window size of the gRPC stream
• Default: 2MB
• Unit: KB|MB|GB
• Minimum value: "1KB"

### grpc-keepalive-time

• The time interval at which that gRPC sends keepalive Ping messages
• Default: "10s"
• Minimum value: "1s"

### grpc-keepalive-timeout

• Disables the timeout for gRPC streams
• Default: "3s"
• Minimum value: "1s"

### concurrent-send-snap-limit

• The maximum number of snapshots sent at the same time
• Default value: 32
• Minimum value: 1

### concurrent-recv-snap-limit

• The maximum number of snapshots received at the same time
• Default value: 32
• Minimum value: 1

### end-point-recursion-limit

• The maximum number of recursive levels allowed when TiKV decodes the Coprocessor DAG expression
• Default value: 1000
• Minimum value: 1

### end-point-request-max-handle-duration

• The longest duration allowed for a client’s push down request to TiKV for processing tasks
• Default value: "60s"
• Minimum value: "1s"

### snap-max-write-bytes-per-sec

• The maximum allowable disk bandwidth when processing snapshots
• Default value: "100MB"
• Unit: KB|MB|GB
• Minimum value: "1KB"

### end-point-slow-log-threshold

• The time threshold for a client’s push down request to print slow log
• Default value: "1s"
• Minimum value: 0

Configuration parameters related to the single thread pool serving read requests. This thread pool supersedes the original storage thread pool and coprocessor thread pool since the 4.0 version.

### min-thread-count

• The minimal working thread count of the unified read pool
• Default value: 1

### max-thread-count

• The maximum working thread count of the unified read pool
• Default value: MAX(4, CPU * 0.8)

### stack-size

• The stack size of the threads in the unified thread pool
• Type: Integer + Unit
• Default value: "10MB"
• Unit: KB|MB|GB
• Minimum value: "2MB"
• Maximum value: The number of Kbytes output in the result of the ulimit -sH command executed in the system.

### max-tasks-per-worker

• The maximum number of tasks allowed for a single thread in the unified read pool. Server Is Busy is returned when the value is exceeded.
• Default value: 2000
• Minimum value: 2

Configuration parameters related to storage thread pool.

### use-unified-pool

• Determines whether to use the unified thread pool (configured in readpool.unified) for storage requests. If the value of this parameter is false, a separate thread pool is used, which is configured through the rest parameters in this section (readpool.storage).
• Default value: If this section (readpool.storage) has no other configurations, the default value is true. Otherwise, for the backward compatibility, the default value is false. Change the configuration in readpool.unified as needed before enabling this option.

### high-concurrency

• The allowable number of concurrent threads that handle high-priority read requests
• When 8cpu num16, the default value is cpu_num * 0.5; when cpu num is greater than 8, the default value is 4; when cpu num is greater than 16, the default value is 8.
• Minimum value: 1

### normal-concurrency

• The allowable number of concurrent threads that handle normal-priority read requests
• When 8cpu num16, the default value is cpu_num * 0.5; when cpu num is greater than 8, the default value is 4; when cpu num is greater than 16, the default value is 8.
• Minimum value: 1

### low-concurrency

• The allowable number of concurrent threads that handle low-priority read requests
• When 8cpu num16, the default value is cpu_num * 0.5; when cpu num is greater than 8, the default value is 4; when cpu num is greater than 16, the default value is 8.
• Minimum value: 1

### max-tasks-per-worker-high

• The maximum number of tasks allowed for a single thread in a high-priority thread pool. Server Is Busy is returned when the value is exceeded.
• Default value: 2000
• Minimum value: 2

### max-tasks-per-worker-normal

• The maximum number of tasks allowed for a single thread in a normal-priority thread pool. Server Is Busy is returned when the value is exceeded.
• Default value: 2000
• Minimum value: 2

### max-tasks-per-worker-low

• The maximum number of tasks allowed for a single thread in a low-priority thread pool. Server Is Busy is returned when the value is exceeded.
• Default value: 2000
• Minimum value: 2

### stack-size

• The stack size of threads in the Storage read thread pool
• Type: Integer + Unit
• Default value: "10MB"
• Unit: KB|MB|GB
• Minimum value: "2MB"
• Maximum value: The number of Kbytes output in the result of the ulimit -sH command executed in the system.

Configuration parameters related to the Coprocessor thread pool.

### use-unified-pool

• Determines whether to use the unified thread pool (configured in readpool.unified) for coprocessor requests. If the value of this parameter is false, a separate thread pool is used, which is configured through the rest parameters in this section (readpool.coprocessor).
• Default value: If none of the parameters in this section (readpool.coprocessor) are set, the default value is true. Otherwise, the default value is false for the backward compatibility. Adjust the configuration parameter in readpool.unified before enabling this parameter.

### high-concurrency

• The allowable number of concurrent threads that handle high-priority Coprocessor requests, such as checkpoints
• Default value: CPU * 0.8
• Minimum value: 1

### normal-concurrency

• The allowable number of concurrent threads that handle normal-priority Coprocessor requests
• Default value: CPU * 0.8
• Minimum value: 1

### low-concurrency

• The allowable number of concurrent threads that handle low-priority Coprocessor requests, such as table scan
• Default value: CPU * 0.8
• Minimum value: 1

### max-tasks-per-worker-high

• The number of tasks allowed for a single thread in a high-priority thread pool. When this number is exceeded, Server Is Busy is returned.
• Default value: 2000
• Minimum value: 2

### max-tasks-per-worker-normal

• The number of tasks allowed for a single thread in a normal-priority thread pool. When this number is exceeded, Server Is Busy is returned.
• Default value: 2000
• Minimum value: 2

### max-tasks-per-worker-low

• The number of tasks allowed for a single thread in a low-priority thread pool. When this number is exceeded, Server Is Busy is returned.
• Default value: 2000
• Minimum value: 2

### stack-size

• The stack size of the thread in the Coprocessor thread pool
• Type: Integer + Unit
• Default value: "10MB"
• Unit: KB|MB|GB
• Minimum value: "2MB"
• Maximum value: The number of Kbytes output in the result of the ulimit -sH command executed in the system.

## storage

Configuration parameters related to storage.

### scheduler-concurrency

• A built-in memory lock mechanism to prevent simultaneous operations on a key. Each key has a hash in a different slot.
• Default value: 524288
• Minimum value: 1

### scheduler-worker-pool-size

• The number of scheduler threads, mainly used for checking transaction consistency before data writing. If the number of CPU cores is greater than or equal to 16, the default value is 8; otherwise, the default value is 4.
• Default value: 4
• Minimum value: 1

### scheduler-pending-write-threshold

• The maximum size of the write queue. A Server Is Busy error is returned for a new write to TiKV when this value is exceeded.
• Default value: "100MB"
• Unit: MB|GB

### reserve-space

• The size of the temporary file that preoccupies the extra space when TiKV is started. The name of temporary file is space_placeholder_file, located in the storage.data-dir directory. When TiKV runs out of disk space and cannot be started normally, you can delete this file as an emergency intervention and set reserve-space to "0MB".
• Default value: "5GB"
• Unite: MB|GB

### enable-ttl

• TTL is short for “Time to live”. If this parameter is enabled, TiKV automatically deletes data that reaches its TTL. To set the value of TTL, you need to specify it in the requests when writing data via the client. If the TTL is not specified, it means that TiKV does not automatically delete the corresponding data.
• Note: The TTL feature is only available for the RawKV interface for now. You can only configure this feature when creating a new cluster because TTL uses different data formats in the storage layer. If you modify this parameter on an existing cluster, TiKV reports errors when it starts.
• Default value: false

### ttl-check-poll-interval

• The interval of checking data to reclaim physical spaces. If data reaches its TTL, TiKV forcibly reclaims its physical space during the check.
• Default value: "12h"
• Minimum value: "0s"

## storage.block-cache

Configuration parameters related to the sharing of block cache among multiple RocksDB Column Families (CF). When these configuration parameters are enabled, block cache separately configured for each column family is disabled.

### shared

• Enables or disables the sharing of block cache.
• Default value: true

### capacity

• The size of the shared block cache.
• Default value: 45% of the size of total system memory
• Unit: KB|MB|GB

## storage.io-rate-limit

Configuration parameters related to I/O rate limiter.

### max-bytes-per-sec

• Limits the maximum I/O bytes that a server can write to or read from the disk (determined by the mode configuration parameter below) in one second. When this limit is reached, TiKV prefers throttling background operations over foreground ones. The value of this configuration parameter should be set to the disk’s optimal I/O bandwidth, for example, the maximum I/O bandwidth specified by your cloud disk vendor. When this configuration value is set to zero, disk I/O operations are not limited.
• Default value: "0MB"

### mode

• Determines which types of I/O operations are counted and restrained below the max-bytes-per-sec threshold. Currently, only the write-only mode is supported.
• Optional value: "write-only"
• Default value: "write-only"

## raftstore

Configuration parameters related to raftstore.

### prevote

• Enables or disables prevote. Enabling this feature helps reduce jitter on the system after recovery from network partition.
• Default value: true

### raftdb-path

• The path to the Raft library, which is storage.data-dir/raft by default
• Default value: "”

### raft-base-tick-interval

• The time interval at which the Raft state machine ticks
• Default value: "1s"
• Minimum value: greater than 0

### raft-heartbeat-ticks

• The number of passed ticks when the heartbeat is sent. This means that a heartbeat is sent at the time interval of raft-base-tick-interval * raft-heartbeat-ticks.
• Default value: 2
• Minimum value: greater than 0

### raft-election-timeout-ticks

• The number of passed ticks when Raft election is initiated. This means that if Raft group is missing the leader, a leader election is initiated approximately after the time interval of raft-base-tick-interval * raft-election-timeout-ticks.
• Default value: 10
• Minimum value: raft-heartbeat-ticks

### raft-min-election-timeout-ticks

• The minimum number of ticks during which the Raft election is initiated. If the number is 0, the value of raft-election-timeout-ticks is used. The value of this parameter must be greater than or equal to raft-election-timeout-ticks.
• Default value: 0
• Minimum value: 0

### raft-max-election-timeout-ticks

• The maximum number of ticks during which the Raft election is initiated. If the number is 0, the value of raft-election-timeout-ticks * 2 is used.
• Default value: 0
• Minimum value: 0

### raft-max-size-per-msg

• The soft limit on the size of a single message packet
• Default value: "1MB"
• Minimum value: 0
• Unit: MB

### raft-max-inflight-msgs

• The number of Raft logs to be confirmed. If this number is exceeded, log sending slows down.
• Default value: 256
• Minimum value: greater than 0

### raft-entry-max-size

• The hard limit on the maximum size of a single log
• Default value: "8MB"
• Minimum value: 0
• Unit: MB|GB

### raft-log-gc-tick-interval

• The time interval at which the polling task of deleting Raft logs is scheduled. 0 means that this feature is disabled.
• Default value: "10s"
• Minimum value: 0

### raft-log-gc-threshold

• The soft limit on the maximum allowable count of residual Raft logs
• Default value: 50
• Minimum value: 1

### raft-log-gc-count-limit

• The hard limit on the allowable number of residual Raft logs
• Default value: the log number that can be accommodated in the 3/4 Region size (calculated as 1MB for each log)
• Minimum value: 0

### raft-log-gc-size-limit

• The hard limit on the allowable size of residual Raft logs
• Default value: 3/4 of the Region size
• Minimum value: greater than 0

### raft-entry-cache-life-time

• The maximum remaining time allowed for the log cache in memory.
• Default value: "30s"
• Minimum value: 0

### raft-reject-transfer-leader-duration

• The protection time for new nodes, which is used to control the shortest interval to migrate a leader to the newly added node. Setting this value too small might cause the failure of leader transfer.
• Default value: "3s"
• Minimum value: 0

### hibernate-regions (Experimental)

• Enables or disables Hibernate Region. When this option is enabled, a Region idle for a long time is automatically set as hibernated. This reduces the extra overhead caused by heartbeat messages between the Raft leader and the followers for idle Regions. You can use raftstore.peer-stale-state-check-interval to modify the heartbeat interval between the leader and the followers of hibernated Regions.
• Default value: true

### raftstore.peer-stale-state-check-interval

• Modifies the state check interval for Regions.
• Default value: 5 min

### split-region-check-tick-interval

• Specifies the interval at which to check whether the Region split is needed. 0 means that this feature is disabled.
• Default value: "10s"
• Minimum value: 0

### region-split-check-diff

• The maximum value by which the Region data is allowed to exceed before Region split
• Default value: 1/16 of the Region size.
• Minimum value: 0

### region-compact-check-interval

• The time interval at which to check whether it is necessary to manually trigger RocksDB compaction. 0 means that this feature is disabled.
• Default value: "5m"
• Minimum value: 0

### region-compact-check-step

• The number of Regions checked at one time for each round of manual compaction
• Default value: 100
• Minimum value: 0

### region-compact-min-tombstones

• The number of tombstones required to trigger RocksDB compaction
• Default value: 10000
• Minimum value: 0

### region-compact-tombstones-percent

• The proportion of tombstone required to trigger RocksDB compaction
• Default value: 30
• Minimum value: 1
• Maximum value: 100

### pd-heartbeat-tick-interval

• The time interval at which a Region’s heartbeat to PD is triggered. 0 means that this feature is disabled.
• Default value: "1m"
• Minimum value: 0

### pd-store-heartbeat-tick-interval

• The time interval at which a store’s heartbeat to PD is triggered. 0 means that this feature is disabled.
• Default value: "10s"
• Minimum value: 0

### snap-mgr-gc-tick-interval

• The time interval at which the recycle of expired snapshot files is triggered. 0 means that this feature is disabled.
• Default value: "1m"
• Minimum value: 0

### snap-gc-timeout

• The longest time for which a snapshot file is saved
• Default value: "4h"
• Minimum value: 0

### lock-cf-compact-interval

• The time interval at which TiKV triggers a manual compaction for the Lock Column Family
• Default value: "256MB"
• Default value: "10m"
• Minimum value: 0

### lock-cf-compact-bytes-threshold

• The size out of which TiKV triggers a manual compaction for the Lock Column Family
• Default value: "256MB"
• Minimum value: 0
• Unit: MB

### notify-capacity

• The longest length of the Region message queue.
• Default value: 40960
• Minimum value: 0

### messages-per-tick

• The maximum number of messages processed per batch
• Default value: 4096
• Minimum value: 0

### max-peer-down-duration

• The longest inactive duration allowed for a peer. A peer with timeout is marked as down, and PD tries to delete it later.
• Default value: "5m"
• Minimum value: 0

### max-leader-missing-duration

• The longest duration allowed for a peer to be in the state where a Raft group is missing the leader. If this value is exceeded, the peer verifies with PD whether the peer has been deleted.
• Default value: "2h"
• Minimum value: greater than abnormal-leader-missing-duration

### abnormal-leader-missing-duration

• The longest duration allowed for a peer to be in the state where a Raft group is missing the leader. If this value is exceeded, the peer is seen as abnormal and marked in metrics and logs.
• Default value: "10m"
• Minimum value: greater than peer-stale-state-check-interval

### peer-stale-state-check-interval

• The time interval to trigger the check for whether a peer is in the state where a Raft group is missing the leader.
• Default value: "5m"
• Minimum value: greater than 2 * election-timeout

### leader-transfer-max-log-lag

• The maximum number of missing logs allowed for the transferee during a Raft leader transfer
• Default value: 128
• Minimum value: 10

### snap-apply-batch-size

• The memory cache size required when the imported snapshot file is written into the disk
• Default value: "10MB"
• Minimum value: 0
• Unit: MB

### consistency-check-interval

• The time interval at which the consistency check is triggered. 0 means that this feature is disabled.
• Default value: "0s"
• Minimum value: 0

### raft-store-max-leader-lease

• The longest trusted period of a Raft leader
• Default value: "9s"
• Minimum value: 0

### allow-remove-leader

• Determines whether to allow deleting the main switch
• Default value: false

### merge-max-log-gap

• The maximum number of missing logs allowed when merge is performed
• Default value: 10
• Minimum value: greater than raft-log-gc-count-limit

### merge-check-tick-interval

• The time interval at which TiKV checks whether a Region needs merge
• Default value: "2s"
• Minimum value: greater than 0

### use-delete-range

• Determines whether to delete data from the rocksdb delete_range interface
• Default value: false

### cleanup-import-sst-interval

• The time interval at which the expired SST file is checked. 0 means that this feature is disabled.
• Default value: "10m"
• Minimum value: 0

### local-read-batch-size

• The maximum number of read requests processed in one batch
• Default value: 1024
• Minimum value: greater than 0

### apply-max-batch-size

• The maximum number of requests for data flushing in one batch
• Default value: 256
• Minimum value: greater than 0

### apply-pool-size

• The allowable number of threads in the pool that flushes data to storage
• Default value: 2
• Minimum value: greater than 0

### store-max-batch-size

• The maximum number of requests processed in one batch
• If hibernate-regions is enabled, the default value is 256. If hibernate-regions is disabled, the default value is 1024.
• Minimum value: greater than 0

### store-pool-size

• The allowable number of threads that process Raft
• Default value: 2
• Minimum value: greater than 0

### future-poll-size

• The allowable number of threads that drive future
• Default value: 1
• Minimum value: greater than 0

## Coprocessor

Configuration parameters related to Coprocessor.

### split-region-on-table

• Determines whether to split Region by table. It is recommended for you to use the feature only with TiDB.
• Default value: false

### batch-split-limit

• The threshold of Region split in batches. Increasing this value speeds up Region split.
• Default value: 10
• Minimum value: 1

### region-max-size

• The maximum size of a Region. When the value is exceeded, the Region splits into many.
• Default value: "144MB"
• Unit: KB|MB|GB

### region-split-size

• The size of the newly split Region. This value is an estimate.
• Default value: "96MB"
• Unit: KB|MB|GB

### region-max-keys

• The maximum allowable number of keys in a Region. When this value is exceeded, the Region splits into many.
• Default value: 1440000

### region-split-keys

• The number of keys in the newly split Region. This value is an estimate.
• Default value: 960000

## RocksDB

Configuration parameters related to RocksDB.

### max-background-jobs

• The number of background threads in RocksDB
• Default value: 8
• Minimum value: 2

### max-background-flushes

• The maximum number of concurrent background memtable flush jobs
• Default value: 2
• Minimum value: 1

### max-sub-compactions

• The number of sub-compaction operations performed concurrently in RocksDB
• Default value: 3
• Minimum value: 1

### max-open-files

• The total number of files that RocksDB can open
• Default value: 40960
• Minimum value: -1

### max-manifest-file-size

• The maximum size of a RocksDB Manifest file
• Default value: "128MB"
• Minimum value: 0
• Unit: B|KB|MB|GB

### create-if-missing

• Determines whether to automatically create a DB switch
• Default value: true

### wal-recovery-mode

• WAL recovery mode
• Optional values: 0 (TolerateCorruptedTailRecords), 1 (AbsoluteConsistency), 2 (PointInTimeRecovery), 3 (SkipAnyCorruptedRecords)
• Default value: 2
• Minimum value: 0
• Maximum value: 3

### wal-dir

• The directory in which WAL files are stored
• Default value: "/tmp/tikv/store"

### wal-ttl-seconds

• The living time of the archived WAL files. When the value is exceeded, the system deletes these files.
• Default value: 0
• Minimum value: 0
• unit: second

### wal-size-limit

• The size limit of the archived WAL files. When the value is exceeded, the system deletes these files.
• Default value: 0
• Minimum value: 0
• Unit: B|KB|MB|GB

### enable-statistics

• Determines whether to enable the statistics of RocksDB
• Default value: true

### stats-dump-period

• The interval at which statistics are output to the log.
• Default value: 10m

### compaction-readahead-size

• The size of readahead when compaction is being performed
• Default value: 0
• Minimum value: 0
• Unit: B|KB|MB|GB

### writable-file-max-buffer-size

• The maximum buffer size used in WritableFileWrite
• Default value: "1MB"
• Minimum value: 0
• Unit: B|KB|MB|GB

### use-direct-io-for-flush-and-compaction

• Determines whether to use O_DIRECT for both reads and writes in background flush and compactions
• Default value: false

### rate-bytes-per-sec

• The maximum rate permitted by RocksDB’s compaction rate limiter
• Default value: 10GB
• Minimum value: 0
• Unit: B|KB|MB|GB

### rate-limiter-mode

• RocksDB’s compaction rate limiter mode
• Optional values: 1 (ReadOnly), 2 (WriteOnly), 3 (AllIo)
• Default value: 2
• Minimum value: 1
• Maximum value: 3

### rate-limiter-auto-tuned

• Determines whether to automatically optimize the configuration of the RocksDB’s compaction rate limiter based on recent workload. When this configuration is enabled, compaction pending bytes will be slightly higher than usual.
• Default value: true

### enable-pipelined-write

• Enables or disables Pipelined Write
• Default value: true

### bytes-per-sync

• The rate at which OS incrementally synchronizes files to disk while these files are being written asynchronously
• Default value: "1MB"
• Minimum value: 0
• Unit: B|KB|MB|GB

### wal-bytes-per-sync

• The rate at which OS incrementally synchronizes WAL files to disk while the WAL files are being written
• Default value: "512KB"
• Minimum value: 0
• Unit: B|KB|MB|GB

### info-log-max-size

• The maximum size of Info log
• Default value: "1GB"
• Minimum value: 0
• Unit: B|KB|MB|GB

### info-log-roll-time

• The time interval at which Info logs are truncated. If the value is 0s, logs are not truncated.
• Default value: "0s"

### info-log-keep-log-file-num

• The maximum number of kept log files
• Default value: 10
• Minimum value: 0

### info-log-dir

• The directory in which logs are stored
• Default value: "”

## rocksdb.titan

Configuration parameters related to Titan.

### enabled

• Enables or disables Titan
• Default value: false

### dirname

• The directory in which the Titan Blob file is stored
• Default value: "titandb"

### disable-gc

• Determines whether to disable Garbage Collection (GC) that Titan performs to Blob files
• Default value: false

### max-background-gc

• The maximum number of GC threads in Titan
• Default value: 4
• Minimum value: 1

## rocksdb.defaultcf

Configuration parameters related to rocksdb.defaultcf.

### block-size

• The default size of a RocksDB block
• Default value: "64KB"
• Minimum value: "1KB"
• Unit: KB|MB|GB

### block-cache-size

• The cache size of a RocksDB block
• Default value: Total machine memory * 25%
• Minimum value: 0
• Unit: KB|MB|GB

### disable-block-cache

• Enables or disables block cache
• Default value: false

### cache-index-and-filter-blocks

• Enables or disables caching index and filter
• Default value: true

### pin-l0-filter-and-index-blocks

• Determines whether to pin the index and filter at L0
• Default value: true

### use-bloom-filter

• Enables or disables bloom filter
• Default value: true

### optimize-filters-for-hits

• Determines whether to optimize the hit ratio of filters
• Default value: true

### whole_key_filtering

• Determines whether to put the entire key to bloom filter
• Default value: true

### bloom-filter-bits-per-key

• The length that bloom filter reserves for each key
• Default value: 10
• unit: byte

### block-based-bloom-filter

• Determines whether each block creates a bloom filter
• Default value: false

### read-amp-bytes-per-bit

• Enables or disables statistics of read amplification.
• Optional values: 0 (disabled), > 0 (enabled).
• Default value: 0
• Minimum value: 0

### compression-per-level

• The default compression algorithm for each level
• Optional values: [“no”, “no”, “lz4”, “lz4”, “lz4”, “zstd”, “zstd”]
• Default value: No for the first two levels, and lz4 for the next five levels

### bottommost-level-compression

• Sets the compression algorithm of the bottommost layer. This configuration parameter overrides the compression-per-level setting.
• Ever since data is written to LSM-tree, RocksDB does not directly adopt the last compression algorithm specified in the compression-per-level array for the bottommost layer. bottommost-level-compression enables the bottommost layer to use the compression algorithm of the best compression effect from the beginning.
• If you do not want to set the compression algorithm for the bottommost layer, set the value of this configuration parameter to disable.
• Default value: “zstd”

### write-buffer-size

• Memtable size
• Default value: "128MB"
• Minimum value: 0
• Unit: KB|MB|GB

### max-write-buffer-number

• The maximum number of memtables
• Default value: 5
• Minimum value: 0

### min-write-buffer-number-to-merge

• The minimum number of memtables required to trigger flush
• Default value: 1
• Minimum value: 0

### max-bytes-for-level-base

• The maximum number of bytes at base level (L1). Generally, it is set to 4 times the size of a memtable.
• Default value: "512MB"
• Minimum value: 0
• Unit: KB|MB|GB

### target-file-size-base

• The size of the target file at base level. This value is overridden by compaction-guard-max-output-file-size when the enable-compaction-guard value is true.
• Default: "8MB"
• Minimum value: 0
• Unit: KB|MB|GB

### level0-file-num-compaction-trigger

• The maximum number of files at L0 that trigger compaction
• Default value: 4
• Minimum value: 0

### level0-slowdown-writes-trigger

• The maximum number of files at L0 that trigger write stall
• Default value: 20
• Minimum value: 0

### level0-stop-writes-trigger

• The maximum number of files at L0 required to completely block write
• Default value: 36
• Minimum value: 0

### max-compaction-bytes

• The maximum number of bytes written into disk per compaction
• Default value: "2GB"
• Minimum value: 0
• Unit: KB|MB|GB

### compaction-pri

• The priority type of compaction
• Optional values: 3 (MinOverlappingRatio), 0 (ByCompensatedSize), 1 (OldestLargestSeqFirst), 2 (OldestSmallestSeqFirst)
• Default value: 3

### dynamic-level-bytes

• Determines whether to optimize dynamic level bytes
• Default value: true

### num-levels

• The maximum number of levels in a RocksDB file
• Default value: 7

### max-bytes-for-level-multiplier

• The default amplification multiple for each layer
• Default value: 10

### rocksdb.defaultcf.compaction-style

• Compaction method
• Optional values: "level", "universal"
• Default value: "level"

### disable-auto-compactions

• Enables or disables automatic compaction
• Default value: false

### soft-pending-compaction-bytes-limit

• The soft limit on the pending compaction bytes
• Default value: "192GB"
• Unit: KB|MB|GB

### hard-pending-compaction-bytes-limit

• The hard limit on the pending compaction bytes
• Default value: "256GB"
• Unit: KB|MB|GB

### enable-compaction-guard

• Enables or disables the compaction guard, which is an optimization to split SST files at TiKV Region boundaries. This optimization can help reduce compaction I/O and allows TiKV to use larger SST file size (thus less SST files overall) and at the time efficiently clean up stale data when migrating Regions.
• Default value: true

### compaction-guard-min-output-file-size

• The minimum SST file size when the compaction guard is enabled. This configuration prevents SST files from being too small when the compaction guard is enabled.
• Default value: "8MB"
• Unit: KB|MB|GB

### compaction-guard-max-output-file-size

• The maximum SST file size when the compaction guard is enabled. The configuration prevents SST files from being too large when the compaction guard is enabled. This configuration overrides target-file-size-base for the same column family.
• Default value: "128MB"
• Unit: KB|MB|GB

## rocksdb.defaultcf.titan

Configuration parameters related to rocksdb.defaultcf.titan.

### min-blob-size

• The smallest value stored in a Blob file. Values smaller than the specified size are stored in the LSM-Tree.
• Default value: "1KB"
• Minimum value: 0
• Unit: KB|MB|GB

### blob-file-compression

• The compression algorithm used in a Blob file
• Optional values: "no", "snappy", "zlib", "bzip2", "lz4", "lz4hc", "zstd"
• Default value: "lz4"

### blob-cache-size

• The cache size of a Blob file
• Default value: "0GB"
• Minimum value: 0
• Unit: KB|MB|GB

### min-gc-batch-size

• The minimum total size of Blob files required to perform GC for one time
• Default value: "16MB"
• Minimum value: 0
• Unit: KB|MB|GB

### max-gc-batch-size

• The maximum total size of Blob files allowed to perform GC for one time
• Default value: "64MB"
• Minimum value: 0
• Unit: KB|MB|GB

### discardable-ratio

• The ratio at which GC is triggered for Blob files. The Blob file can be selected for GC only if the proportion of the invalid values in a Blob file exceeds this ratio.
• Default value: 0.5
• Minimum value: 0
• Maximum value: 1

### sample-ratio

• The ratio of (data read from a Blob file/the entire Blob file) when sampling the file during GC
• Default value: 0.1
• Minimum value: 0
• Maximum value: 1

### merge-small-file-threshold

• When the size of a Blob file is smaller than this value, the Blob file might still be selected for GC. In this situation, discardable-ratio is ignored.
• Default value: "8MB"
• Minimum value: 0
• Unit: KB|MB|GB

### blob-run-mode

• Specifies the running mode of Titan.
• Optional values:
• normal: Writes data to the blob file when the value size exceeds min-blob-size.
• read_only: Refuses to write new data to the blob file, but still reads the original data from the blob file.
• fallback: Writes data in the blob file back to LSM.
• Default value: normal

### level-merge

• Determines whether to optimize the read performance. When level-merge is enabled, there is more write amplification.
• Default value: false

### gc-merge-rewrite

• Determines whether to use the merge operator to write back blob indexes for Titan GC. When gc-merge-rewrite is enabled, it reduces the effect of Titan GC on the writes in the foreground.
• Default value: false

## rocksdb.writecf

Configuration parameters related to rocksdb.writecf.

### block-cache-size

• Block cache size
• Default value: Total machine memory * 15%
• Unit: MB|GB

### optimize-filters-for-hits

• Determines whether to optimize the hit ratio of the filter
• Default value: false

### whole-key-filtering

• Determines whether to put the entire key to bloom filter
• Default value: false

### enable-compaction-guard

• Enables or disables the compaction guard, which is an optimization to split SST files at TiKV Region boundaries. This optimization can help reduce compaction I/O and allows TiKV to use larger SST file size (thus less SST files overall) and at the time efficiently clean up stale data when migrating Regions.
• Default value: true

### compaction-guard-min-output-file-size

• The minimum SST file size when the compaction guard is enabled. This configuration prevents SST files from being too small when the compaction guard is enabled.
• Default value: "8MB"
• Unit: KB|MB|GB

### compaction-guard-max-output-file-size

• The maximum SST file size when the compaction guard is enabled. The configuration prevents SST files from being too large when the compaction guard is enabled. This configuration overrides target-file-size-base for the same column family.
• Default value: "128MB"
• Unit: KB|MB|GB

## rocksdb.lockcf

Configuration parameters related to rocksdb.lockcf.

### block-cache-size

• Block cache size
• Default value: Total machine memory * 2%
• Unit: MB|GB

### optimize-filters-for-hits

• Determines whether to optimize the hit ratio of the filter
• Default value: false

### level0-file-num-compaction-trigger

• The number of files at L0 required to trigger compaction
• Default value: 1

## raftdb

Configuration parameters related to raftdb.

### max-background-jobs

• The number of background threads in RocksDB
• Default value: 4
• Minimum value: 2

### max-sub-compactions

• The number of concurrent sub-compaction operations performed in RocksDB
• Default value: 2
• Minimum value: 1

### wal-dir

• The directory in which WAL files are stored
• Default value: "/tmp/tikv/store"

## security

Configuration parameters related to security.

### ca-path

• The path of the CA file
• Default value: "”

### cert-path

• The path of the Privacy Enhanced Mail (PEM) file that contains the X509 certificate
• Default value: "”

### key-path

• The path of the PEM file that contains the X509 key
• Default value: "”

### redact-info-log

• This configuration parameter enables or disables log redaction. If the configuration value is set to true, all user data in the log will be replaced by ?.
• Default value: false

## security.encryption

Configuration parameters related to encryption at rest (TDE).

### data-encryption-method

• The encryption method for data files
• Value options: “plaintext”, “aes128-ctr”, “aes192-ctr”, and “aes256-ctr”
• A value other than “plaintext” means that encryption is enabled, in which case the master key must be specified.
• Default value: "plaintext"

### data-key-rotation-period

• Specifies how often TiKV rotates the data encryption key.
• Default value: 7d

### enable-file-dictionary-log

• Enables the optimization to reduce I/O and mutex contention when TiKV manages the encryption metadata.
• To avoid possible compatibility issues when this configuration parameter is enabled (by default), see Encryption at Rest - Compatibility between TiKV versions for details.
• Default value: true

### previous-master-key

• Specifies the old master key when rotating the new master key. The configuration format is the same as that of master-key. To learn how to configure a master key, see Encryption at Rest - Configure encryption.

## import

Configuration parameters related to TiDB Lightning import and BR restore.

### num-threads

• The number of threads to process RPC requests
• Default value: 8
• Minimum value: 1

### num-import-jobs

• The number of jobs imported concurrently
• Default value: 8
• Minimum value: 1

## gc

The configuration parameter related to gc.

### enable-compaction-filter

• Controls whether to enable the GC in Compaction Filter feature
• Default value: false

## backup

The configuration parameter related to BR backup.

### num-threads

• The number of worker threads to process backup
• Default value: MIN(CPU * 0.75, 32).
• Minimum value: 1

## cdc

Configuration parameters related to TiCDC.

### min-ts-interval

• The interval at which Resolved TS is calculated and forwarded.
• Default value: "1s"

### old-value-cache-size

• The entry number of TiCDC old values cached in memory.
• Default value: 1024

### incremental-scan-speed-limit

• The maximum speed at which historical data is incrementally scanned.
• Default value: "128MB", which means 128 MB per second.

## pessimistic-txn

### wait-for-lock-timeout

• The longest time that a pessimistic transaction in TiKV waits for other transactions to release the lock. If the time is out, an error is returned to client, and client retries to add a lock. The lock wait timeout is set by innodb_lock_wait_timeout.
• Default value: "1s"
• Minimum value: "1ms"

### wait-up-delay-duration

• When pessimistic transactions release the lock, among all the transactions waiting for lock, only the transaction with the smallest start_ts is woken up. Other transactions will be woken up after wait-up-delay-duration.
• Default value: "20ms"

### pipelined

• This configuration parameter enables the pipelined process of adding the pessimistic lock. With this feature enabled, after detecting that data can be locked, TiKV immediately notifies client to execute the subsequent requests and write the pessimistic lock asynchronously, which reduces most of the latency and significantly improves the performance of pessimistic transactions. But there is a still low probability that the asynchronous write of the pessimistic lock fails, which might cause the failure of pessimistic transaction commits.
• Default value: true